表没食子儿茶素没食子酸酯和茶黄素对秀丽隐杆线虫耐温性的影响

Effects of epigallocatechin gallate and theaflavin on temperature tolerance of Caenorhabditis elegans

为探究绿茶和红茶中的代表性组分对秀丽隐杆线虫在不同温度条件下的作用效果及机制,试验设置0.25、2.5、25μmol/L表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)和茶黄素(theaflavin,TF1),测定线虫在4℃和35℃条件下的存活率,进而测定在4℃、20℃和30℃条件下经25μmol/L EGCG和TF1孵育后线虫体内脂肪含量和线粒体膜电位的变化。结果显示,25μmol/L EGCG将热应激线虫的最大寿命和中位寿命分别提高了8.15%、22.44%,将冷应激线虫的最大寿命和中位寿命分别降低了20.25%、17.94%。25μmol/L TF1对热应激线虫的存活率无显著影响,将冷应激线虫的最大寿命和中位寿命分别提高了9.43%、19.01%。在4℃条件下,EGCG和TF1孵育均提高了线虫体内的脂肪含量,TF1孵育降低了线虫的线粒体膜电位水平。在20℃条件下,EGCG和TF1具有明显的降脂作用,长时间孵育可显著提高衰老线虫线粒体活性。在30℃条件下,EGCG和TF1提高了线虫体内的脂肪含量。以上结果表明,在低温条件下TF1通过促进线粒体产热而非脂肪动员提高了线虫的存活率,而EGCG孵育可诱导线虫死亡。

In order to investigate the effect and underlying mechanism of representative components of green tea and black tea on nematodes(Caenorhabditis elegans)at different temperature,the survival rate of nematodes at 4℃and 35℃were quantified in the presence of 0.25,2.5 and 25μmol/L epigallocatechin gallate(EGCG)or theaflavin(TF1).Then,fat content and mitochondrial membrane potentials were investigated in nematodes incubated with 25μmol/L EGCG and TF at 4℃,20℃and 30℃were determined.The results showed that 25μmol/L EGCG increased the maximum and median lifespan of heat stressed nematodes by 8.15%and 22.44%,respectively,and decreased the maximum and median lifespan of cold stressed nematodes by 20.25%and 17.94%,respectively.25μmol/L TF1 had no significant effect on the survival rate of heat-stressed nematodes,but increased the maximum and median lifespan of coldstressed nematodes by 9.43%and 19.01%,respectively.At 4℃,both EGCG and TF1 incubation increased the fat content of nematodes and TF1 incubation decreased the mitochondrial membrane potential of nematodes.At 20℃,EGCG and TF1 showed significant lipid-lowering effect and could significantly improve the mitochondrial activity in senescent nematodes after long-term incubation.At 30℃,EGCG and TF1 increased the fat content in nematodes.The results indicated that TF1 improves the survival rate of nematodes by promoting mitochondrial thermogenesis rather than fat mobilization under low temperature conditions,whereas EGCG incubation can induce nematode death.